Answer:
Meiosis is important because it ensures that all organisms produced via sexual reproduction contain the correct number of chromosomes.
Explanation:
Answer:
The best explanation if we observe an epithelial cell with chromosomes are visible and two cell nuclei is that the cell has just gone through telophase but not cytokinesis (option b).
Explanation:
A somatic cell, when found in mitosis, exhibits the chromosomes distributed in both poles and the outline of two nuclei in the telophase phase, just before cytokinesis.
In mitotic telophase:
- Chromatids, which are chromosomes, are found in the cell poles.
- It initiates the formation of the nucleus membrane.
- The chromosomes begin to turn into chromatin.
- Disappearance of the mitotic spindle, duplication of organelles and cytoplasmic invagination.
The division and differentiation of the nuclei in telophase is called karyokinesis. Later, cytokinesis occurs, where the daughter cells are separated.
The other options are not correct because:
<em> a and d. In the other phases described, </em><em><u>S and G1,</u></em><em> no chromosome distribution is observed at the poles.</em>
<em> c. A somatic cell does not experience </em><em><u>meiosis</u></em><em>.</em>
Answer:
It depends on the battlefield.
Explanation:
sea going crocodile would win in the sea while jaguar would win on land.
Answer:
A. NADH and FADH2 both donate electrons at the same location.
Explanation:
In the respiratory chain, four large protein complexes inserted into the mitochondrial inner membrane transport NADH and FADH₂ electrons (formed in glycolysis and the Krebs cycle) to oxygen gas, reducing them to NAD⁺ and FAD, respectively.
These electrons have great affinity for oxygen gas and, when combined with it, reduce it to water molecules at the end of the reaction.
Oxygen gas effectively participates in cellular respiration at this stage, so its absence would imply interruption of the process.
NADH and FADH₂ electrons, when attracted to oxygen, travel a path through protein complexes, releasing energy in this process.
The energy released by the NADH and FADH₂ electrons in the respiratory chain in theory yields <u>34</u> <u>ATP</u>, however, under normal conditions an average of 26 ATP molecules is formed.
If we consider that these 26 molecules are added to the two ATP formed in glycolysis and two ATP formed in the Krebs cycle, it can be said that cellular respiration reaches a maximum yield of 30 ATP per glucose molecule, although theoretically this number was 38 ATP per glucose molecule.
Gynecomastia is an increase in the size of the mammary gland in men. The condition can occur in one or both breasts. It starts as a small mass under the nipple, which can be sensitive. One breast can be bigger than the other. Its cause is an imbalance between the stimulatory effects of estrogen (female sex hormones) and the inhibitory effects of androgens (male sex hormones) in the breast tissue, when the first ones increase, or the second ones descend.
Gynecomastia is a problem relatively common in the population, and there are three prevalence peaks throughout life:
Newborns: Between 60 and 90% of newborns have gynecomastia, produced by the passage of maternal estrogens through the placenta. It is a transient gynecomastia that disappears in about 2-3 weeks.
Puberty: Gynecomastia in puberty affects mainly young people aged between 10 and 14 years, and is due to the transient and physiological increase in estrogen that occurs at this age.
Elderly: Is due to an increase in fatty tissue with a greater peripheral aromatization ( a process that occurs in adipose tissue and that involves the conversion of androgens into estrogens), a decrease in the production of testosterone by the testes and the use of drugs.
